Means for and method of testing stay-bolts.



E. I. DODDSl MEANS FOR AND METHOD 0F TESTING STAY BoLTs.

APPLICATION FILED FEB. I8, 1916L l ,9536,4. Patented Aug. 7, 1917.

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ETHAN I. DODDS, OF PITTSBURGH,

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PENNSYLVANIA, ASSIGNOR TO FLANNERY BOLT COMPANY, OF PITTSBURGH, ."EENNSYLVANIA.

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Specification of Letters Ztatent.`

Patented Aug. 7, 1917.

Application filed 'February 18, 1916. Serial No. 79,137.

To all fr0/0m t may Concern.'

Be it known that I, ETI-miv I. DoDDs, a citizen of the United States, and a resi-dent of Pittsburgh, in the county of Billegheny and State of Pennsylvania, have invented certain new and useful Improvements in Means for and Methods of Testing Stay- Bolts; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to means for and the method of testing stay bolts of boilers,- one object of the invention being to provide simple and etiicient means whereby broken stay bolts in a boiler' structure may be detected.

i further object is to provide a magnetic testing device which will, when applied in proximity to the head of a stay bolt in a boiler structure, cause the integrity or severance of the bolt to be definitely manifested.

A further object is to provide an improved method of testing boiler stay bolts while the same are in place in the boiler structure for the purpose of detecting broken bolts.

`lilith these and other objects in view, the i vention consists in certain novel steps in the method of testing stay bolts and in certain novel features of construction and combinations of parts as hereinafter set forth and pointed out in the claims.

In the accompanying drawings; Figure 1 is a view illustrating the application of my improvements; Fig. 2 is a View partly in section and partly in elevation, and Fig. 3 is a plan view.

In the application of stay bolts to boilers, it is customary to attach one end of the bolt to the inner boiler sheet 2 and to provide the other end of the bolt with a spherical or partly spherical head 3 having a bearing in a sleeve t passing through the outer sheet 5 of the structure. This sleeve is externally threaded to facilitate its attachment to the sheet 5 and also to receive a cap 6 which incloses the head of the bolt,-the structure of the assembled parts being such as to leave a clearance 7 between the head 3 of the bolt and the inner face of the cap. Should theJ bolt break at any point, the head thereof will become loose within the cap 6 and may move therein through the clearance space 7 and engage the inner face of said cap.

My improved detector is designed to cause the head of a broken stay-bolt to forcibly engage the cap and by the sound or vibration produced by the striking of the bolt head against the cap, denote the fact that the bolt is broken. Should no sound or vibration occur when the detector is vapplied, this fact will denote the integrity of the bolt.

My improved testing vdevice or detector comprises a magnet frame 8 so formed as to provide a core portion 9 and a housing 10 preferably made integral therewith. The core and housing 10 form an annular space or chamber in which a coil 11 is located.

A plate 12, preferably of brass or other non-magnetic metal, closes the bottom of the magnet frame and is made with a central enlargement 13 having a partly spherical recess 14 therein. The plate 12 is made with a central-hole communicating with the recess 14, for the passage of a screw 15, of magnetic metal. This screw enters the core 9 of the magnet and its head 16 is seated -within the upper portion of the recess 14.

In this manner the non-magnetic plate 12 is secured to the magnet frame and prevents displacement of the coil 11. Suitable insulating material 17 is disposed between the coil and the members 9 and 10 of the magnet and the bottom plate 12.

A handle 18 is secured to the magnet frame 1 and may be made hollow to receive a plug 19 carrying a suitable switch indicated at 20, and also to facilitate the introduction of leading-in-wires from any suitable source of electrical supply.

The leading-in wires, illustrated diagrammatically at 21 pass through the hollow handle and after suitable connection with the switch 20, are led through a fuse block 22 secured upon the magnet frame and linally to the terminals 23 of the magnet coil 11.

The recess 14 in the plate 12 is of suitable I size and form as to receive a portion of the cap 6 of the stay bolt structure and permit said cap to engage the head of the iron screw 15. When the device is thus applied, the closing of the circuit of the magnet coil will result in the generation of magnetic lines of force which will pass through the iron cap of the stay bolt structure, thus magnetizing said cap in such manner as to cause the head of the stay bolt to be attracted thereto and forcibly engage the same,

in the event that the bolt is broken. Such forcible engagement of the bolt head with the cap will cause a sharp sound or jar which will indicate to the operator that the bolt is broken, viz. that the parts thereof have become severed.

By providing the deviee with a non-me tallic plate, such as the plate l2 and forming such plate with a socket to receive the stay bolt cap with the head of the iron screw l5 in said socket, the path of the lines of force will be so diverted from the lower pole of the magnet core as to be caused to pass through a considerable portion of the cap 6 and even through parts of the stay bolt, before reaching the other pole of the magnet. In other words, the non-magnetic plate will'operate to prevent undue short-circuiting of the lines of force through the housing of the magnetic frame, but insures their passage through the cap 6 of the stay bolt structure.

Should the bolt break in proximity to the inner sheet 2, it would be liable to drop to an inclined position and the head might bind in its bearing in the sleeve 4 due possibly to a collection of incrustation which might enter by reason of the loosened bearing of the head of the broken bolt. Under such conditions, a magnet structure such as above described may be applied to the inner head of the broken bolt so as to cause the body of the depending broken bolt to-be Copies of this patent may be obtained for ve cents each, by addressing the raised or moved sufliciently to insure the operation of the magnet structure applied to the cap to cause the head of the bolt to strike the cap as previously explained.

Having fully described my invention what I claim as new and desire to secure by Letters-Patent, is

l. Testing means for stay bolts, comprising a magnet frame7 a coil therein, a nonmagnetie plate at the lower end of said magnet frame7 said plate having an enlarge ment provided with a recess to receive the cap of a stay bolt structure, a screw of magnetic material securing said plate to the core of the magnet frame, and means for controlling the circuit of said coil.

2. The method of testing staybolts embodied in boiler structures and having inclosing caps for their outer extremities, such method consisting in magnetizing such caps and noting whether there is a shifting of a part of the bolt by determining whether there is a noise incident to the striking of such part of the bolt against the cap of the structure.

In. testimony whereof, I have signed this specication in the presence of two subscribing witnesses.

ETI-IAN I. DODDS.

Witnesses:

R. L. FERGUSON,

S. C. H111..

Commissioner of Patents,

Washington, D. C. 

